This invention relates to a circular knitting machine with at least one first part in the form of a carrier having knitting implements, a second part in the form of a cam system having cam system groups being distributed along the periphery of the cylinder and having adjustable cam system parts and setting means, and a setting device which can be aligned with the cam system groups and which includes at least one actuating member adapted to adjust the cam system parts in accordance with a pattern.
In multi-system circular knitting machines there is frequently a desire to facilitate the production of different patterns, especially knit patterns, by changing the cam system groups. If a complete change of the cam system arrangements in order to alter the pattern is to be avoided, adjustable cam system parts are provided, which remain in fixed adjustment for the duration of manufacture of a selected knitwear but which can be rapidly switched into another position when needed, in that setting means associated with the cam system parts are operated on with a tool, the setting means consisting of levers, eccentrics or setting pins or the like with inclined surfaces for example. The switching over is effected manually as a rule and with the machine out of operation. Regardless of whether cam system parts are involved in the particular case which move parallel to or perpendicular to the knitting needles (DE 4 240 037 A1 or EP 0 694 640 A1), such switching over can mostly be effected from the outside and without stripping down.
In spite of the setting facilities for the cam system parts, simple in themselves, the conversion of a circular knitting machine is comparatively time-consuming, especially when a multi-system, high capacity circular knitting machine is involved. In a circular knitting machine which has two needle tracks and 72 knitting systems, a complete changeover of all cam system parts takes about two and a half hours and longer for example.
In addition a circular knitting machine of the kind initially referred to is already known (DE-AS 1 122 662), which comprises stationary cam system groups and a rotating setting device with an actuating member in the form of switching rod, which can act on setting means coupled to the cam system parts, in the form of star or cross shaped rotary parts. If the actuating member is located in an operative position produced in accordance with a pattern, it turns the rotary part on through an angular increment of 90.degree. in each case as it passes by a cam system group, whereby the associated cam system part is switched alternately to the one or the other of two possible positions. On the other hand, if the actuating member is in an inoperative position it allows the rotary part to pass by unaffected, so that the cam system part involved remains in that position which had been produced in the preceding passage of the actuating member in the operative position. The setting device is fixed in a circular knitting machine with a rotatable needle cylinder to a machine part rotating therewith, so that it passes all cam system groups distributed in the circumferential direction of the needle cylinder or the dial one after the other and adjusts its cam system parts in accordance with the pattern. In a circular knitting machine with a rotating cam system the setting device would arranged on an immovable machine part, so that the rotating cam system groups would pass by it one after the other. An advantage of such a setting device consists in that the cam system parts can be set automatically in that the actuating member is moved selectively into the operative or inoperative position, e.g. by electromagnets controllable in accordance with the pattern.
In circular knitting machine of the kind described the setting device serves exclusively the purpose of switching the cam system parts during operation into the one or the other position in accordance with the pattern. The setting device would in principle also be suitable for adjusting the cam system parts between two working cycles of the circular knitting machine and thus tool up for the next following working cycle. However the disadvantage would arise with this that the control of the actuating member into its operative or inoperative position would have to be effected not only in dependence on the desired pattern, but also in dependence on which position the cam system part to be switched already arbitrarily occupies. This cannot be effected in practice in multi-system circular knitting machines, because the design of a knitting pattern and the calculation of the pattern data controlling the actuating member required to realise the pattern has to be independent of knowledge of which pattern the circular knitting machine in question was already arbitrarily set to.
Finally circular knitting machines are known (DE-AS 1 228 746, DE-PS 1 246 153) which comprise rotating guide tracks for controlling pivoted levers coupled to the cam system parts or individual pattern drums associated with the knitting systems, which are turned on by a control chain and have pins for setting the cam system parts. Such setting devices are mechanically complex and not usable for high capacity machines.